Radio signaling system



y 1933- A. L. BUDLONG 1,909,805

' RADIO SIGNALING SYSTEM Filed March 20, 1928 THY/FIZZ?! 4 L Buc/Mng Patented May 16, 1933 UN TED STATES ARTHUR L. BUnLon'G, or HARTFORD, connnc'rrcur RADIO SIGNALING SYSTEM Application filed March 20, 1928. Serial No. 263,071.

This invention relates in general to radio signaling systems.

One of the objects of the invention isthe' provision of a new type of radio signaling system particularly adapted for the recepincoming signals are detected by means of a suitable detecting device and the detected signals are used to modulate a constant high frequency current and the modulated current is then amplified and detected.

A further object of this invention involves the combination with a radio frequency amplifier circuitofa source of sustained oscillations and the output circiut of a suitable detecting device. These and other objects as will appear from the following disclosure are sought by means of this invention. 7

This invention resides substantially in the combination, construction, arrangement and relative location of parts and circuital connections as will appear more fully hereinafter. p Referring to the drawing, the single figure is a diagrammatic illustration of the relative association of elements employed in this invention.

An inspection of the drawing will disclose that this invention fundamentally comprises a detector circuit, an oscillator Cir-- cuit, an amplifier circuit and a second de tector circuit. The first detector circuit and the oscillator circuit are associated with the input of theradio frequency amplifier circuit so that the detected incoming signal current will modulate the constant high frequency currents. The combination current isthen amplified and detected.

For a better understanding of the inven- 1 tion reference is made to the drawing in which the usual earth antenna system is 0 shown at 1 and 3 connected together through denser 13 connected across the grid inductance 11. It IS, of course, to be understood an inductance 2. The inductance is variably associated with another inductance 4 connected in the grid filament circuit of the three electrode audion detector tube A. The variablecondenser 5 is shunted across the inductance 4 and provides a means for tun-' ing the input of the detector tube.- The grid lead of this tube is provided as usual with the combination condenser andpresistance 6 to provide a grid leak. A fixed condenser 9 is connected across the filament and plate of the tube A to provide a high frequency by-pass. The filament of this tube is supplied by means of a suitable current source 7 and the current supplied thereto is regulated by means of a variable resistance 8. The plate circuit of the tube A includes the primary 10 of an audio frequency transformer, the return lead of this primary being adjustably connected to the current source 30.

At B is shown a three electrode audion tube having circuit arrangements to provide with it the high frequency fixed by-pass con-i denser 14. The filament of this tube is shunted across the current source By means of this arrangement the input and output circuits of the tube B are connected together to provide a source of constant" radio frequency currents. The frequency of the oscillations generated by this arrangement is controlled by means of the conthat any suitable form of radio frequency generator could be used in this arrangement.

At C is shown a three electrode audion tube arranged to provide a radiofrequency amplifier. The grid filament circuit of this tube is provided with the'secondary l5 of the audio frequency transformer and. a. second inductance 18. A. fixed capacity 16 is, shunted across the inductance "15m provide a radio frequency by-pass. A variable condenser 17 is provided for tuning the inductance 18. The inductance 18 is inductively associated with the inductance 12 in the output circuit of the oscillator tube B so that the constant radio frequency currents generated thereby are impressed upon the input circuit of the radio frequency amplifier tube C. The detected signal currents supplied to the audio frequency transformer are introduced into the input circuit of the tube C by means of the secondary of this transformer and they modulate the radio frequency currents. The filament of the tube C is connected to the current source 7 The plate circuits of the tubes 13 and G are supplied with current from the source 30.

The plate filament circuitrof the tube C includes an inductance 19 which is associated with the grid filament circuit of the second detector tube I) by means of the inductance 20 included therein. The grid lead of this tube includes the usual grid leak system 21. If desired the inductances 19 and 20 may be tuned by condensers. The filament of the tube D receives its current from the source 7 and the amount of currents applied to all the filaments is controlled by means of the resistance 8. The plate circuit 'of the tube I) includes some form of electrically operated sound reproducing device and this circuit is adjustably connected to the current source 30.

Theoperation of this device follows. The signal waves impressed upon the antenna 1 How through the inductance 2 and are trans ferred to the tuned circuit l-5 where they are detected by the vacuum tube A. The detected currents are impressed upon the input circuit of the tube C through the agency of the audio frequency transformer. The radio frequency oscillator B likewise supplies current at constant radio frequency to the input of the tube C through the inductance 18. These high frequency currents are modulated by the detected currents and the resultant current passes through the tube C and is amplified thereby. This amplified resultant current is detected in the circuits of the tube D and transformed into sound waves by means of the sound reproducing device 22.

I am well aware that numerous changes in the details of construction and relative association of parts will readily occur to those skilled in the art without departing from this invention. For instance, if desired a tickler coil could be included in the plate circuit of the tube A to provide regeneration of the signal current if desired; any suitable type of high frequency current oscillator-could be employed in place of the oscillator tube B; one or more audio frequency amplifier stages could beincluded between the detector A and the audio frequency transformer; more than one radio quency oscillations could be generated in the first detector tube A in which case it would be possible eitherto modulate the constant oscillations in the amplifying tube C or even in the detector tube A itself. Likewise the output of the first detector could be coupled to the input of the oscillator,

modulating the generated oscillations in this tube and the output of the oscillator could then be coupled to the input of the radio frequency amplifier by any suitable means. I do not, therefore, desire to be limited except as required by the appended claims.

What I seek to secure by UnitedStates Letters Patent is: v

'1. In a radio receiving system the combination with an input circuit, a detector circuit and a source of constant high frequency sustained oscillations of an amplifier circuit said amplifier circuit inductively coupled to both said detector and source of high frequency oscillations. I

2. In a system for the reception of radiant energy, the combination with an input circuit, a three electrode detector tube including input and output circuits and an audion generator of radio frequency currents of constant frequency, of a three electrode ra dio frequency amplifier includingan input circuit inductively coupled to both the output circuit of said three electrode detector and the output circuit of said audion gener ator and asecond detector coupled to the output circuit of said radio frequency amplifier.

3. The method of receiving radio signals which comprises converting the received signal currents into audio-frequency currents, generating high frequency currents, modulating the high frequency currents with said audio frequency currents, amplifying the modulated high frequency currents, and p r 'ing the sustained high frequency currents,

and finally detecting the modulated sustained high frequency currents. q

5. In a radio system for the receipt of signals in combination with an input circuit a detector having an output clrcu'it and a instead of the oscillator-B the radio fresource of constant high frequency sustained oscillations having an output circuit of an audio frequency coupling device, a radio frequency amplifier having its input circuit electro-magnetically coupled to the output circuit of said detector through said coupling device, and a radio frequency coupling device adapted to couple the output circuit of the source of continued high frequency oscillations also with said input circuit of said radio frequency amplifier.

6. In a radio system for receiving signals, the combination with a detector and an oscillator of an amplifier inductively coupled through an audio frequency transformer to said detector and through a radio frequency transformer to said oscillator, saidv radio frequency amplifier having an output circuit in which the combined currents from said detector and oscillator flow, and a three electrode audion detector coupled to said putput circuit of said radio frequency ampliier.

7. In a radio system for the receipt of signals, the combination with an input circuit, a vacuum tube detector coupled to said input circuit, said detector having an output circuit, and a generator of constant high frequency sustained oscillations, of a radio frequency amplifier having input and output circuits, means in the output circuit of said detector, and means in the input circuit of said amplifier in the nature of an electromagnetic audio frequency coupling device, and further means in the output circuit of said oscillator and in the input circuit of said amplifier in the nature of a radio frequency coupling device for combining the detected current and the constant high frequency current and a second detector coupled to the output circuit of said radio frequency amplifier.

In testimony whereof I have hereunto set my hand on this 16th day of March A. D.,

ARTHUR L. BUDLONG. 

